svn commit: r285656 - in head/sys: kern sys
Ed Schouten
ed at FreeBSD.org
Fri Jul 17 16:34:03 UTC 2015
Author: ed
Date: Fri Jul 17 16:34:01 2015
New Revision: 285656
URL: https://svnweb.freebsd.org/changeset/base/285656
Log:
Add an API for easily creating userspace threads in kernelspace.
This change refactors the existing create_thread() function to be more
generic. It replaces almost all of its arguments by a callback that can
be used to extract the thread ID and copy it out to the right place, but
also to perform additional initialization steps, such as setting the
trapframe. This also makes the difference between thr_new() and
thr_create() more clear in my opinion.
This function is going to be used by the CloudABI compatibility layer.
Reviewed by: kib
MFC after: 1 month
Modified:
head/sys/kern/kern_thr.c
head/sys/sys/proc.h
Modified: head/sys/kern/kern_thr.c
==============================================================================
--- head/sys/kern/kern_thr.c Fri Jul 17 14:33:47 2015 (r285655)
+++ head/sys/kern/kern_thr.c Fri Jul 17 16:34:01 2015 (r285656)
@@ -89,29 +89,39 @@ suword_lwpid(void *addr, lwpid_t lwpid)
#define suword_lwpid suword
#endif
-static int create_thread(struct thread *td, mcontext_t *ctx,
- void (*start_func)(void *), void *arg,
- char *stack_base, size_t stack_size,
- char *tls_base,
- long *child_tid, long *parent_tid,
- int flags, struct rtprio *rtp);
-
/*
* System call interface.
*/
+
+struct thr_create_initthr_args {
+ ucontext_t ctx;
+ long *tid;
+};
+
+static int
+thr_create_initthr(struct thread *td, void *thunk)
+{
+ struct thr_create_initthr_args *args;
+
+ /* Copy out the child tid. */
+ args = thunk;
+ if (args->tid != NULL && suword_lwpid(args->tid, td->td_tid))
+ return (EFAULT);
+
+ return (set_mcontext(td, &args->ctx.uc_mcontext));
+}
+
int
sys_thr_create(struct thread *td, struct thr_create_args *uap)
/* ucontext_t *ctx, long *id, int flags */
{
- ucontext_t ctx;
+ struct thr_create_initthr_args args;
int error;
- if ((error = copyin(uap->ctx, &ctx, sizeof(ctx))))
+ if ((error = copyin(uap->ctx, &args.ctx, sizeof(args.ctx))))
return (error);
-
- error = create_thread(td, &ctx.uc_mcontext, NULL, NULL,
- NULL, 0, NULL, uap->id, NULL, uap->flags, NULL);
- return (error);
+ args.tid = uap->id;
+ return (thread_create(td, NULL, thr_create_initthr, &args));
}
int
@@ -129,6 +139,35 @@ sys_thr_new(struct thread *td, struct th
return (kern_thr_new(td, ¶m));
}
+static int
+thr_new_initthr(struct thread *td, void *thunk)
+{
+ stack_t stack;
+ struct thr_param *param;
+
+ /*
+ * Here we copy out tid to two places, one for child and one
+ * for parent, because pthread can create a detached thread,
+ * if parent wants to safely access child tid, it has to provide
+ * its storage, because child thread may exit quickly and
+ * memory is freed before parent thread can access it.
+ */
+ param = thunk;
+ if ((param->child_tid != NULL &&
+ suword_lwpid(param->child_tid, td->td_tid)) ||
+ (param->parent_tid != NULL &&
+ suword_lwpid(param->parent_tid, td->td_tid)))
+ return (EFAULT);
+
+ /* Set up our machine context. */
+ stack.ss_sp = param->stack_base;
+ stack.ss_size = param->stack_size;
+ /* Set upcall address to user thread entry function. */
+ cpu_set_upcall_kse(td, param->start_func, param->arg, &stack);
+ /* Setup user TLS address and TLS pointer register. */
+ return (cpu_set_user_tls(td, param->tls_base));
+}
+
int
kern_thr_new(struct thread *td, struct thr_param *param)
{
@@ -142,22 +181,13 @@ kern_thr_new(struct thread *td, struct t
return (error);
rtpp = &rtp;
}
- error = create_thread(td, NULL, param->start_func, param->arg,
- param->stack_base, param->stack_size, param->tls_base,
- param->child_tid, param->parent_tid, param->flags,
- rtpp);
- return (error);
+ return (thread_create(td, rtpp, thr_new_initthr, param));
}
-static int
-create_thread(struct thread *td, mcontext_t *ctx,
- void (*start_func)(void *), void *arg,
- char *stack_base, size_t stack_size,
- char *tls_base,
- long *child_tid, long *parent_tid,
- int flags, struct rtprio *rtp)
+int
+thread_create(struct thread *td, struct rtprio *rtp,
+ int (*initialize_thread)(struct thread *, void *), void *thunk)
{
- stack_t stack;
struct thread *newtd;
struct proc *p;
int error;
@@ -199,24 +229,6 @@ create_thread(struct thread *td, mcontex
cpu_set_upcall(newtd, td);
- /*
- * Try the copyout as soon as we allocate the td so we don't
- * have to tear things down in a failure case below.
- * Here we copy out tid to two places, one for child and one
- * for parent, because pthread can create a detached thread,
- * if parent wants to safely access child tid, it has to provide
- * its storage, because child thread may exit quickly and
- * memory is freed before parent thread can access it.
- */
- if ((child_tid != NULL &&
- suword_lwpid(child_tid, newtd->td_tid)) ||
- (parent_tid != NULL &&
- suword_lwpid(parent_tid, newtd->td_tid))) {
- thread_free(newtd);
- error = EFAULT;
- goto fail;
- }
-
bzero(&newtd->td_startzero,
__rangeof(struct thread, td_startzero, td_endzero));
bcopy(&td->td_startcopy, &newtd->td_startcopy,
@@ -224,26 +236,11 @@ create_thread(struct thread *td, mcontex
newtd->td_proc = td->td_proc;
thread_cow_get(newtd, td);
- if (ctx != NULL) { /* old way to set user context */
- error = set_mcontext(newtd, ctx);
- if (error != 0) {
- thread_cow_free(newtd);
- thread_free(newtd);
- goto fail;
- }
- } else {
- /* Set up our machine context. */
- stack.ss_sp = stack_base;
- stack.ss_size = stack_size;
- /* Set upcall address to user thread entry function. */
- cpu_set_upcall_kse(newtd, start_func, arg, &stack);
- /* Setup user TLS address and TLS pointer register. */
- error = cpu_set_user_tls(newtd, tls_base);
- if (error != 0) {
- thread_cow_free(newtd);
- thread_free(newtd);
- goto fail;
- }
+ error = initialize_thread(newtd, thunk);
+ if (error != 0) {
+ thread_cow_free(newtd);
+ thread_free(newtd);
+ goto fail;
}
PROC_LOCK(p);
Modified: head/sys/sys/proc.h
==============================================================================
--- head/sys/sys/proc.h Fri Jul 17 14:33:47 2015 (r285655)
+++ head/sys/sys/proc.h Fri Jul 17 16:34:01 2015 (r285656)
@@ -992,6 +992,8 @@ void thread_cow_get_proc(struct thread *
void thread_cow_get(struct thread *newtd, struct thread *td);
void thread_cow_free(struct thread *td);
void thread_cow_update(struct thread *td);
+int thread_create(struct thread *td, struct rtprio *rtp,
+ int (*initialize_thread)(struct thread *, void *), void *thunk);
void thread_exit(void) __dead2;
void thread_free(struct thread *td);
void thread_link(struct thread *td, struct proc *p);
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